We propose to study the expression of specific genes in cellular, chromatin and purified systems. These include the following defined genes: human/rat insulin, three rat amylase genes, hepatitis virus DNA (4 genes) (all transcribed by RNA polymerase III, and yeast 358 ribosomal RNA (RNA polymerase I) and 5S, tRNA genes RNA polymerase I. Insulin, amylase, hepatitis virus genes expression will be studied in Xenopus oocytes, in transformed/transfected cells (SV40) that do/do not express the genes. Determination and modification of DNA segments controlling expression and site-directed integration into chromosomes is proposed. Chromatin of expressing/non-expressing cells will be analyzed by DNAse digestion, specific expression of genes in chromatin and in extracts employed to identify transcription specific factors. RNA polymerase I, RNA polymerase transcription factors indentified by simplification of pure ribosomal chromatin (yeast) and from extracts/yeast Xenopus. Role of factors in controlling expression of these genes will be studied.